1. Field of the Invention
The invention relates in general to heat dissipating assemblies and, in particular, to an improved two piece clip for maintaining a heat dissipating element in heat transferring relationship with an electronic device such as an electronic chip used in computers.
2. Description of the Prior Art
In order to safely operate many of today's computers and other electronic devices, heat must be removed from components which generate large amounts of heat and which cannot dissipate the heat fast enough to avoid harmful consequences. One method for dissipating the accumulating heat of an electronic device is to force air over the device, thereby removing the heat by convection. This method has been substantially improved by attaching a heat dissipating device to the electronic device wherein the heat dissipating device is designed to dissipate heat at a significantly greater rate than the electronic device alone. Such a device typically has projections such as pins or fins, exposing a greater surface area to the flow of air for greater dissipation of heat. Hinshaw U.S. Pat. Nos. 4,884,331 and 4,879,891 disclose one type of pinned and finned heat sink.
When the heat dissipating device is placed in contact with the electronic device, the electronic device transfers heat by conduction to the heat dissipating device which then dissipates accumulating heat by convection. This method has become standard among the computer industry for dissipating the large amounts of heat generated by the new generation of computer processors.
Many different methods have been used to secure the heat dissipating device to the electronic device, including the use of clips to fasten the assembly together. Clips generally extend over the heat sink and attach at each end to the electronic device or its socket at specially provided ports or bosses. Such one piece clips are illustrated for example in the heat dissipating assemblies described in Blomquist U.S. Pat. No. 5,208,731, issued May 4, 1993, and Blomquist U.S. patent application Ser. No. 08/289,925, filed Aug. 12, 1994, now U.S. Pat. No. 5,486,981. It is preferred that any securing method devised allow for quick and easy attachment and removal of the heat dissipating device while providing a secure attachment during operation and normal handling. Electronic devices must be removed and replace from time to time, and so it is necessary that the heat dissipating assembly should be easy to remove and install without sacrificing reliability or effectiveness. Clips offer the advantage of being inexpensive, simple, operational over a multiple number of assembles and disassembles, and reasonably secure so that the heat dissipating device does not disconnect or dislodge from the electronic device.
Previous heat dissipating assemblies utilizing a two piece clip as a fastening means had generally lacked sufficient rigidity and strength, particularly at the junction between the two parts of the clip, and separation of the assembly had been a potential risk. In general, prior two piece clips had been constructed so that the intersection of the separate leg and the leaf spring member formed a loose hinge about which rotation at least to some degree in several directions was possible. Thus, the force holding the assembly together was exerted substantially entirely in a direction normal to the electronic component. The hinge mechanism was relatively weak and prone to failure, particularly under prolonged use and shock and vibration. Holding the necessary tolerances during manufacturing imposed additional difficulty in producing prior two piece clips.
These and other difficulties of the prior art have been overcome according to the present invention.